Dental instrument



y 1944- H. R. BERGER 2,349,607

- DENTAL INSTRUMENT Filed Nov. 28, 1941 INVENTOR HERB .55 2

ATTORN EY Patented May 23, 1944 DENTAL INSTRUMENT Herbert It. Berger,Brooklyn, N. Y., assignor to Mizzy, Inc., New York, N. Y., a corporationof New York Application November 28, 1941, Serial No. 420,762

2 Claims.

This invention relates to dental instruments and more particularly to aninstrument for injecting material into the prepared cavity of a tooth tomake an impression thereof, preparatory to producing the filling orinlay to be fitted into said cavity.

Much difiiculty has been encountered in making a proper impression. Somedentists merely apply a piece of wax to the tooth and then lift the samedepending upon their expertness to achieve proper results. Others makeuse of an impression band placed around the tooth and fill the band withimpression material by hand. Neither method has been found satisfactorybecause of either inaccuracies in the impression or the incorporationtherein of air bubbles because sufficient pressure could not be employedfor forcing the impression material into the cavity.

The primary object of the present invention, therefore, is to provide aninstrument whereby an exact impression of a cavity may be obtained in anexpeditious manner and with minimum discomfort to the patient.

Another object of the invention is to provide an instrument in which theimpression material is conveniently loaded and in which handling thereofis facilitated.

A further object resides in the provision of an instrument in which theimpression material may be heated for ready flowing thereof, saidinstrument yet being comfortable to handle during manipulation.

The inexpensive and fool-proof design of the instrument whereby itsrange of application is enlarged, also forms a material part of theinvention.

The foregoing objects and other objects, features and advantages of theinvention will become more clearly evident from the followingspecification in which the invention is described with particularreference to the illustrated embodiment shown in the accompanyingdrawing.

In the drawing- Fig. 1 is a side view, partly in section, of aninstrument incorporating features of the invention as applied to make animpression of a tooth cavity.

Fig. 2 is an end view thereof.

Fig. 3 is a broken side view, somewhat differently fitted, of theinstrument shown in Fig. 1.

In that form of the invention which is illustrated, the instrumentcomprises a barrel 5, and a piston or plunger 6 connected by a stem 1 toa hand-piece 8. The above is quite conventional,

following the usual forms of extrusion syringes of that general type.

In the present instance, the instrument is provided with a flange 6aforming a shoulder for a finger-piece 9 strung over said barrel. Ascontemplated, said finger-piece is connected, as by the threads in, to aheat insulating sleeve ll completely surrounding the barrel 5.

At its end opposite to the flange 6a, the barrel is fitted with a nozzlel2 which is threadedly engaged as at I3 for ready removal andreplacement.

The nozzle is formed with a passage I 4 having communication with thebore of the barrel 5 and terminates in a flanged seat l5 at its outerend. The nozzle may be made in a plurality of forms as a set wherebyselection of a nozzle which provides for most comfortable and effectivehandling of the instrument, is afforded. Thus, the nozzle shown in Fig.1 has its seat directed at right angles to the longitudinal dimension ofthe barrel so that a fitting I 6, set into the seat I5, is arranged atright angles to said barrel, and the nozzle l2a shown in Fig. 3 has itsseat directed at a lesser angle with respect to the barrel length sothat a fitting l6a, set into its seat, is arranged at a commensuratelylesser angle with respect to said body.

The provision of a set of such nozzles, each varying as set forth, willafford the user the greatest ease and comfort in applying theinstrument. Inasmuch as the sleeve l l is made removable for reasonslater apparent, it is preferred that said sleeve be adapted to beremoved and replaced with the nozzle in position on the barrel. Hence,the edge I! of the flanged seat I5 is curved in accordance with thecurvature of the barrel as can be understood.

The instrument above described is employed for obtaining a waximpression of, for instance, the cavity I8 of a tooth l9. Preparatory toshooting wax into said cavity, it is preferred to place an impressionband 20 around said tooth as shown, said band having a top edge 2|engageable by a preferably concavely curved face 22 formed on thefitting I6. A central passage 23 in said fitting communicates thepassage M with the interior of the impression band as shown.

It will be noted that the fittings l5 and Ilia may also be made in sets,each with a flare or flange 24 of different size. A proper fitting maythus be selected according to the size of the impression band and theamount of space afforded for manipulating the instrument in use.

When an impression is to be made, the band 20 is placed in position onthe tooth having the cavity. The sleeve II and nozzle l2 are removed andthe plunger 6 retracted. Into the bore of the barrel is placed a stickor cartridge of impression wax which may comprise either hydro-colloids,elastic compounds, or regular compoundsall available to the dentist. Thenozzle l2 or [2a is then replaced and the barrel heated to soften ormelt the wax. It will be noted that the instrument cannot be used inthis condition since the finger-piece 9 forms part of the sleeve H whichhad been removed.

After heating of the wax, the sleeve II is replaced on the barrel tocover the same and afford protection against hand burns to the user, orburns to the patient. The finger-piece 9 being in position, theinstrument may be properly grasped. The fitting I6 or Ilia is appliedagainst the impression band as shown and the plunger 6 projected toforce the softened wax through the passages Hand 23 into the impressionband 20 and into the tooth cavity Ill.

The user continues projecting Wax until an extrusion thereof appearsaround the bottom of the impression band at which time assurance is hadthat the entire interior of the band, except the space occupied by thetooth, is completely filled with wax. The fitting I6, by means of theinstrument which serves as a handle, is then removed from contact withthe band with a wiping motion. After the wax has set, the impressionband, together with the wax is lifted from the tooth and used forcasting the filling or inlay.

Because of the plastic state of the wax while being applied, assuranceis had that all the interstices of the cavity have been filled and thatthe impression is free of air bubbles--a common cause of failure inprior methods.

In practice it has been found that a cartridge of wax is easier placedinto the barrel from the handle end thereof and does not require theremoval of the nozzle l2. For this purpose, the

flange 6a is made removable from the barrel 5 so that the plunger 6 maybe removed to give access to the bore of the barrel. A threadedengagement of these parts at 25 is, therefore, provided.

The instrument herein disclosed may have other uses than that described,it being effective in any connection for the purpose of extrudingplastic material.

In the above manner, and by employing the novel instrument hereindescribed, an impression may be quickly and accurately made with aminimum of discomfort to the patient and with no danger of burns inhandling the heated wax or the heated barrel. Broad facility ofoperation is afforded by the judicious selection of a suitable nozzleand fitting, and assurance that a sharp impression has been made.

From the foregoing it can be seen that an efficient instrument has beenprovided for the purpose intended. However, since the invention issubject to variations within the spirit and scope of the followingclaims, it is intended that this disclosure be considered as by way ofexample only.

I claim:

1. In an instrument of the extrusion syringe type having a barrel, anozzle removably attached thereto, the outside of the barrel and thenozzle presenting a smooth, cylindrical, outer surface, a removableinsulating sleeve for said barrel having affixed thereto a finger-piecefor the instrument, and said sleeve having a smooth interior cylindricalsurface.

2. In an instrument of the extrusion syringe type having a barrel, anozzle replaceably carried by said barrel, a seat in the end of saidnozzle receptive selectively of any of a plurality of nozzle fittings,the outside of the barrel and the nozzle forminga smooth cylindricalouter surface, a removable insulating sleeve for said barrel, and afinger-piece for said instrument affixed to said sleeve, said sleevehaving a smooth interior cylindrical surface whereby the sleeve may beremoved from and replaced over said barrel while the nozzle is in placeon the barrel.

HERBERT R. BERGER.

